Acute corporeal fluxes of sodium, water and other electrolytes occur after thermal trauma and are important in the pathogenesis of burn shock and its treatment, but these phenomena are incompletely understood. This clinical and laboratory study has two objectives: 1) To further elucidate the magnitude and relative importance of sodium, water and other electrolyte fluxes in burn shock and its fluid treatment, principally by appropriate analysis of tissues of relative cellularity, relative acellularity and intermediate cellularity both in burned experimental animals and in severely burned man. 2) To conduct a prospective controlled clinical study of the fluid treatment of burn shock using one of three currently recommended clinical protocols in more or less general use: a) Lactated Ringer's solution alone, b) lactated Ringer's solution and colloid (plasma) in the ratio of 2 to 1 ("Brooke formula") and c) hypertonic lactated saline solution (250 mEq Na/L). In addition to assessment of the usual clinical, chemical and hemodynamic parameters, serial tissue samples (principally of dermis and skeletal muscle) will be obtained from the subjects and analyzed in an effort to delineate the effects of injury and therapy on the mineral and water composition of both burned and unburned tissues. We hope to at least partially answer 4 questions: 1) Is traumatic edema obligatory and fixed in amount or can it be reduced or accentuated significantly by variation in loads of sodium, water and colloid administered for resuscitation? 2) What are the effects of fluid resuscitation on traumatized tissues and on those remote from the injury? 3) What are the relationships between relatively acellular and cellular tissues in their response to thermal injury? 4) What is the best (most physiological) method for clinical fluid resuscitation after burn?